1. Field
The presently disclosed subject matter relates to an optical semiconductor device module used in a head lamp or the like of a vehicle.
2. Description of the Related Art
Generally, in the same way as a chip resistor module and a chip capacitor module, an optical semiconductor device module or a light emitting diode (LED) module mounted on a vehicle is constructed by fixing an LED element to a mounting substrate, using solder portions, screws or spot welds, which will be explained later in detail.
However, when the LED element is fixed directly to the mounting substrate using solder portions, screws or spot welds, cracks could occur in the solder portions, the lead frames could be deformed, or the LED element could break down. This also will be explained later in detail.
In order to easily replace the LED element with a new one, other approaches are to press lead frames onto a mounting substrate by a detachable cover (see: JP-2003-101072A), to press lead frames onto a mounting substrate by metal plates (see: JP-2003-243721A), to fix lead frames to a mounting substrate by a locking component (see: JP-2003-331635A), to press lead frames onto a mounting substrate by fitting metal plates (see: JP-2003-347598A), and to fix lead frames to a housing by fitting attachments (see: JP-2006-066108A, JP-2006-302714A and JP-2007-141549A).
However, when the metal plates or attachments are used, an opening for the LED element is required in the metal plates or attachments, so that the light emitting portion and lens of the LED element could be damaged which would invite the reduction of light flux and the deterioration of light distribution. On the other hand, when the metal plates or attachments are fitted into the mounting substrate or housing, the contact characteristics of a new LED element could deteriorate after the metal plates or attachments are again fitted into the mounting substrate or housing.
A further prior art optical semiconductor device module is constructed by an LED element having a light emitting portion on its top surface, a mounting substrate for mounting the LED element thereon, and two conductive leaf springs for fixing the LED element to the mounting substrate and supplying power to the LED element. In this case, each of the leaf springs is formed by a plurality of rectangularly-shaped terminals of the same shape (see: FIG. 15 of JP-2007-141549A).
In the further prior art optical semiconductor device module, however, since the rectangularly-shaped terminals have the same shape so that their natural frequencies are the same, when one of the rectangularly-shaped terminals vibrates due to vibration of a vehicle, the other rectangularly-shaped terminals simultaneously vibrate, i.e., resonate. Thus, the vibration of the leaf springs is enhanced, so that lightening and darkening of the LED element would be repeated, and at worst, the LED element would be separated from the mounting substrate.